It most commonly occurs in people with elevated systemic levels of estrogen, classically in women taking estrogen-containing oral contraceptive medication.

[3][4] The significance of making a specific diagnosis is that, unlike other benign liver tumors such as hemangioma and focal nodular hyperplasia, hepatic adenomas have a small but meaningful risk of progressing into a malignancy.

[citation needed] Hepatic adenomas may be sub-classified according to morphologic appearance by microscopy, immunohistochemical staining, and genetic mutational analysis:[5][6][7] Although the significance of this categorization is still under research, the subtypes may indicate differential risk of hemorrhage or malignant transformation.

[citation needed] Hepatic adenomas are, typically, well-circumscribed nodules that consist of sheets of hepatocytes with a bubbly vacuolated cytoplasm.

Other medications which also alter circulating hormone levels, such as anabolic or androgenic steroids, Barbiturates, clomifene, have also been implicated as risk factors.